Lesson 10 · A very-narrow-aisle warehouse

A very-narrow-aisle (VNA) warehouse stores pallets in tall racks on both sides of an aisle just wider than a truck. You will draw the aisle on a path, give a turret truck the pallet it handles, fill the racks halfway, and let two block sequences store and retrieve pallets while you watch the forks work in 3D.

Open your project from lesson 9, or its checkpoint. Zoom out and pan so there is room to the left of the loop: the annex is 20 m long.

How the warehouse is modelled

Cell

one pallet position, identified by aisle, side, column and level, never by name.

Stop

one physical place per column where the truck stops, shared by both sides and all levels: 10 columns × 4 levels × 2 sides give 80 cells and 10 stops.

Exchange station

an ordinary station outside the aisle where pallets enter and leave the warehouse. A store takes the pallet there, a retrieve brings it there.

One mission per aisle

only one warehouse mission is admitted per aisle at a time, covering the approach, the service and the way out. The aisle is protected like an exclusive zone, for through traffic too.

The annex and its stations

1. Draw the annex path. In Draw choose Path (4). Click on the left side of the loop at (−10 000, 0) (the start snaps onto the middle of that side), then click (−30 000, 0), 20 m to the left. Zoom out and pan with the wheel until both points are on screen. Leave the direction on Both · A ↔ B: a dead-end aisle needs a path the truck can leave again.
2. Place the exchange station. With Station, click on the annex near (−12 500, 0). Name it WH in and tick both Pickup and Drop-off: pallets are left here to be stored and brought here when retrieved. It must lie outside the aisle, with room for a truck to turn.
3. Place a parking for the truck. Click near (−16 000, 0), name it VNA park and tick Parking. It sits beyond the exchange station, off the platforms' way.

The VNA truck

1. Add the fleet. In Simulate › Vehicles, click Add fleet. Name it VNA, set Type to VNA truck and leave one AGV. The card loads the truck's preset: 3000 × 1100 mm, 100 cm/s on straights and 30 on curves, 25 seconds to pick up and 25 to drop off. Every value stays editable, and only this type serves warehouses.
2. Set its lift. In VNA warehouse, set Maximum height to 6000 mm; Lift speed 30 and Lowering speed 40 cm/s are already the preset. The pallet defaults to a EUR pallet, 1200 × 800 mm, with the short side facing the aisle (Aisle side): the forks enter through the 800 mm side, so 800 mm of the pallet runs along the aisle and 1200 mm goes into the rack. All VNA fleets share one pallet.
3. Reserve the stations. In Draw, select VNA park and leave only VNA ticked in Permitted fleets. Select WH in and untick Heavy: the platforms bring pallets and the truck stores them, the forklifts have no business here.

Draw the aisle

1. Choose the Warehouse tool. Click Warehouse and click on the annex near (−19 000, 0), then near (−28 000, 0). Both clicks snap onto the same straight path, and the aisle rounds to whole cells sized for the truck's pallet. Between the two clicks a preview shows the racks and the stops; the second click creates the aisle as one undo step, with its ends marked A and B. The panel on the right opens with a name you can change.
2. Set the geometry. In Structure: Name A01, Sides Both, Positions per side 10, Pallets per bay 1 and Start (mm) 9000: the racks begin 9 m from the path's start, leaving room for the exchange station and the parking. Cell pitch (mm) and Depth (mm) already follow the pallet (900 and 1100 mm); Fit to pallet would reset them if you change the pallet. Levels is 4, at 0, 1800, 3600 and 5400 mm: every height below the truck's 6000 mm.
3. Connect the aisle. In Entries and exits, set End A (the end nearer the loop) to WH in and leave Allows on Entry and exit; End B stays Closed. This is the only way in or out of the aisle, and the line below the fields reads it as a dead end.
4. Apply the changes. Press Apply warehouse: your changes to the aisle apply as one undo step. The racks stand on both sides: 10 columns × 4 levels × 2 sides = 80 cells, served by 10 stops, one per column. Until you apply them, the pending changes block Save.
5. Fill it halfway. Open Initial inventory to see the rack elevation. Set Initial occupancy (%) to 50 and press Replace stock: forty pallets are spread evenly over the usable cells, the same each time. Cells are empty, occupied, reserved by an order or blocked.

Store and retrieve with blocks

A workflow replaces the periodic generator, warehouse flows included, so the pallets move through blocks. Two blocks do it: Store reserves the fastest free cell and sends a vehicle to take a pallet at the exchange station and put it there; Retrieve reserves the fastest available pallet and brings it to the exchange station. If the warehouse is full or empty the request waits, without taking a vehicle or the aisle.

1. Add the two sequences. In Plant logic, below your other sequences, add the two rows above. In each Store or Retrieve block, choose WH in as Exchange station and tick the aisle A01.
2. Check the scenario. In Simulate a new first step, Warehouse, shows 1 aisles · 40/80: one aisle, 40 cells occupied out of 80. The fleet step reads 5/5 AGV · 3 fleets.

Run it and look

1. Run one hour. Press Start run for 1 h. In Results a Warehouse section lists the usable capacity (80), the pallets stored now, and the deposits and retrievals completed. A pallet is stored every two minutes and one retrieved every two and a half, so the stock slowly rises from 40 towards 46.
2. Open the 3D view. While it runs or paused, click the cube button, 3D view, in the toolbar. Drag to rotate, scroll to pan, and hold Ctrl while scrolling to zoom. Racks with pallets stand on both sides of the aisle; the truck's mast stands on its chassis and its turret head swivels towards the cell, the slide carries the pallet in, and the forks come back before lowering. Another click returns to 2D; neither restarts the run.

Checkpoint

It contains: 11 paths · 10 stations · 1 traffic zone · 1 warehouse aisle · 5 AGVs · 3 fleets · 19 workflow blocks.

Download the checkpoint (aurora-10-warehouse.en.sim)

Open it with Project›Import project. It replaces the project you have open, so save yours first (or open it in a new browser tab). Anything you do from here on is a copy: the checkpoint file itself never changes. Use it to continue from here if you skipped a lesson, or to compare your own project with the expected one.